1. Field
This disclosure relates to flight control systems for missiles, and particularly to missiles that incorporate thrust vectoring for attitude control.
2. Description of the Related Art
Missiles commonly include aerodynamic control surfaces such as fins, ailerons, rudders, flaps, canards, and other surfaces to control the attitude, or direction of travel, of the missile. However aerodynamic control surfaces may be ineffective at low velocities after missile launch, and may be ineffective at high altitudes at the upper extent or beyond the atmosphere. Thus missiles may also use thrust vectoring to control attitude at low speeds and/or high altitudes. In this context, thrust vectoring is defined as directing the thrust of a rocket motor or jet engine in a direction that is not parallel to a longitudinal axis of the missile.
Thrust vectoring is conventionally used to control pitch and yaw attitude, or elevation angle and azimuth angle. For example, thrust vectoring for large rocket motors may be accomplished by rotating the entire exhaust nozzle of the motor. For smaller rocket motors, thrust vectoring may be accomplished using rotatable devices, which may be aerodynamic vanes or fins, extending into the motor exhaust stream within or behind the motor nozzle. Since devices extending into the motor exhaust stream typically reduce the total thrust produced by the motor, thrust vectoring devices may be withdrawn from the exhaust stream when the missile has reach sufficient velocity to be control by aerodynamic control surfaces. However, thrust vectoring devices that can be both rotated and withdrawn in the environment of a rocket motor exhaust stream require complex actuation mechanisms.
Throughout this description, elements appearing in figures are assigned three-digit reference designators, where the most significant digit is the figure number and the two least significant digits are specific to the element. An element that is not described in conjunction with a figure may be presumed to have the same characteristics and function as a previously-described element having a reference designator with the same least significant digits.